In wireless networks, successful data transmission requires a transmitter to transmit a signal with an energy per bit that is large enough for a receiver to distinguish the signal from noise. Free space propagation causes energy of the signal to decay with the inverse of the distance squared. Thus, maintaining sufficient energy per bit such that the transmission is successful as the range is increased requires that either the power of the transmission is increased or the number of bits transmitted per unit time is decreased or a combination of both.